Ubuntu12.04下pulseaudio的安装以及API使用

一、Ubuntu12.04下安装音频库客户端软件libpulse-dev

Package libpulse-dev：PulseAudio client development headers and libraries

使用如下命令：

sudo apt-get install libpulse-dev

安装时会提示依赖于下面这几个软件，一并安装即可：

libavahi-client-dev libavahi-common-dev libpulse-mainloop-glib0 libpulse0

这个也可以上packages.ubuntu.com官方网址查询libpulse-dev软件的依赖关系，相关链接如下：

http://packages.ubuntu.com/raring/libpulse-dev

如下图所示：

二、pulseaudio库的使用（同步simple API）

pulseaudio官网有关于pulseaudio的API doxygen使用手册，网址如下：

http://freedesktop.org/software/pulseaudio/doxygen/

1、播音sample

A simple playback tool using the simple API

//pacat-simple.c/***This file is part of PulseAudio.PulseAudio is free software; you can redistribute it and/or modifyit under the terms of the GNU Lesser General Public License as publishedby the Free Software Foundation; either version 2.1 of the License,or (at your option) any later version.PulseAudio is distributed in the hope that it will be useful, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNUGeneral Public License for more details.You should have received a copy of the GNU Lesser General Public Licensealong with PulseAudio; if not, write to the Free SoftwareFoundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307USA.***/#ifdef HAVE_CONFIG_H#include <config.h>#endif#include <stdio.h>#include <unistd.h>#include <string.h>#include <errno.h>#include <fcntl.h>#include <pulse/simple.h>#include <pulse/error.h>#define BUFSIZE 1024int main(int argc, char*argv[]) {/* The Sample format to use */static const pa_sample_spec ss = {.format = PA_SAMPLE_S16LE,.rate = 44100,.channels = 2};pa_simple *s = NULL;int ret = 1;int error;/* replace STDIN with the specified file if needed */if (argc > 1) {int fd;if ((fd = open(argv[1], O_RDONLY)) < 0) {fprintf(stderr, __FILE__": open() failed: %s\n", strerror(errno));goto finish;}if (dup2(fd, STDIN_FILENO) < 0) {fprintf(stderr, __FILE__": dup2() failed: %s\n", strerror(errno));goto finish;}close(fd);}/* Create a new playback stream */if (!(s = pa_simple_new(NULL, argv[0], PA_STREAM_PLAYBACK, NULL, "playback", &ss, NULL, NULL, &error))) {fprintf(stderr, __FILE__": pa_simple_new() failed: %s\n", pa_strerror(error));goto finish;}for (;;) {uint8_t buf[BUFSIZE];ssize_t r;#if 0pa_usec_t latency;if ((latency = pa_simple_get_latency(s, &error)) == (pa_usec_t) -1) {fprintf(stderr, __FILE__": pa_simple_get_latency() failed: %s\n", pa_strerror(error));goto finish;}fprintf(stderr, "%0.0f usec \r", (float)latency);#endif/* Read some data ... */if ((r = read(STDIN_FILENO, buf, sizeof(buf))) <= 0) {if (r == 0) /* EOF */break;fprintf(stderr, __FILE__": read() failed: %s\n", strerror(errno));goto finish;}/* ... and play it */if (pa_simple_write(s, buf, (size_t) r, &error) < 0) {fprintf(stderr, __FILE__": pa_simple_write() failed: %s\n", pa_strerror(error));goto finish;}}/* Make sure that every single sample was played */if (pa_simple_drain(s, &error) < 0) {fprintf(stderr, __FILE__": pa_simple_drain() failed: %s\n", pa_strerror(error));goto finish;}ret = 0;finish:if (s)pa_simple_free(s);return ret;}

2、录音sample

A simple recording tool using the simple API

//parec-simple.c/***This file is part of PulseAudio.PulseAudio is free software; you can redistribute it and/or modifyit under the terms of the GNU Lesser General Public License as publishedby the Free Software Foundation; either version 2.1 of the License,or (at your option) any later version.PulseAudio is distributed in the hope that it will be useful, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNUGeneral Public License for more details.You should have received a copy of the GNU Lesser General Public Licensealong with PulseAudio; if not, write to the Free SoftwareFoundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307USA.***/#ifdef HAVE_CONFIG_H#include <config.h>#endif#include <stdio.h>#include <unistd.h>#include <string.h>#include <errno.h>#include <pulse/simple.h>#include <pulse/error.h>#define BUFSIZE 1024/* A simple routine calling UNIX write() in a loop */static ssize_t loop_write(int fd, const void*data, size_t size) {ssize_t ret = 0;while (size > 0) {ssize_t r;if ((r = write(fd, data, size)) < 0)return r;if (r == 0)break;ret += r;data = (const uint8_t*) data + r;size -= (size_t) r;}return ret;}int main(int argc, char*argv[]) {/* The sample type to use */static const pa_sample_spec ss = {.format = PA_SAMPLE_S16LE,.rate = 44100,.channels = 2};pa_simple *s = NULL;int ret = 1;int error;/* Create the recording stream */if (!(s = pa_simple_new(NULL, argv[0], PA_STREAM_RECORD, NULL, "record", &ss, NULL, NULL, &error))) {fprintf(stderr, __FILE__": pa_simple_new() failed: %s\n", pa_strerror(error));goto finish;}for (;;) {uint8_t buf[BUFSIZE];/* Record some data ... */if (pa_simple_read(s, buf, sizeof(buf), &error) < 0) {fprintf(stderr, __FILE__": pa_simple_read() failed: %s\n", pa_strerror(error));goto finish;}/* And write it to STDOUT */if (loop_write(STDOUT_FILENO, buf, sizeof(buf)) != sizeof(buf)) {fprintf(stderr, __FILE__": write() failed: %s\n", strerror(errno));goto finish;}}ret = 0;finish:if (s)pa_simple_free(s);return ret;}

3、编译、运行含有pulseaudio库的时候，需要添加pulseaudio的动态链接库-libpulse等，

(可以在/usr/lib/i386-linux-gnu/目录下找到pulse的动态库

/usr/lib/i386-linux-gnu/libpulsecommon-1.1.so
/usr/lib/i386-linux-gnu/libpulsedsp.so
/usr/lib/i386-linux-gnu/libpulse-mainloop-glib.so
/usr/lib/i386-linux-gnu/libpulse-mainloop-glib.so.0
/usr/lib/i386-linux-gnu/libpulse-mainloop-glib.so.0.0.4
/usr/lib/i386-linux-gnu/libpulse-simple.so
/usr/lib/i386-linux-gnu/libpulse-simple.so.0
/usr/lib/i386-linux-gnu/libpulse-simple.so.0.0.3
/usr/lib/i386-linux-gnu/libpulse.so
/usr/lib/i386-linux-gnu/libpulse.so.0
/usr/lib/i386-linux-gnu/libpulse.so.0.13.5)

例如,以pacat-simple.c程序为例：

(1)编译命令如下：

 gcc -o pacat-simple pacat-simple.c -lpulse -lpulsecommon-1.1 -lpulse-simple
(2)运行上一步生成的pacat-simple可执行程序

./pacat-simple 飞鸟.wav

(注意：有一个命令行参数，是音频文件名，上网搜索一个wav格式的音频文件，放在当前目录，然后执行。)

三、ALSA音频库

ALSA全称为：Advanced Linux Sound Architecture

一个网址为：http://www.alsa-project.org/main/index.php/Main_Page